Electric switch



Ap 122,1941. J.J.ZE..LER 2,2 9,071

ELECTRIC SWITCH Filed NOV. 1.3, 1937 2 Sheets-Sheet l April 22, 1941.

Filed Nov. 1:s, 1937 J. J. ZELL ER 2,239,071

ELECTRIC SWITCH 2 Sheets-Sheet 2 IN VENTUR J'osayfi $26126).-

A TTOR/VEV right angles and attached to a. float l3.

Patented Apr. 22,1941

ELECTRIC SWITCH Joseph J. Zeller, Detroit, Mich, assignor to Square D Company, Detroit, Mich., a corporation 01' Michigan Application November 13, 1937, Serial No. 174,407

12 Claims.

This invention relates to an electric switch operable to on and off positions in response to an external condition and is particularly adapted, although not limited, to operation in response to variations in liquid level.

One object of the invention is the provision of an electric switch in which the contacts are biased in their closed position by a. magnetic force and held in their disengaged position by latching means and in which resilient means are provided for moving contacts against the magnetic bias to their disengaged position.

Another object of the invention is the provision of an improved form of a float operated electric switch providing a simplified and economically operated mechanism.

Further objects and features of this invention will be readily apparent to those skilled in the art from the following specification and appended drawings illustrating certain embodiments of the invention in which:

Figure 1 is a front elevational view of the de-' vice according to the present invention with a portion of the tank to which it is attached broken away to show the float therein.

Figure 2 is an enlarged front elevational view with the cover of the switch removed.

Figure 3 is a vertical sectional view on the line III-III of Figure 1.

Figure 4 is a horizontal sectional view on the line IV-IV of Figure 2.

Figure 5 is a vertical sectional view on the line V-V of Figure 2.

Figure 6 is a horizontal sectional view on the line VI-VI of Figure 2.

The switch and float unit according to the present invention comprises a large plug I adapted to be threaded into an appropriate socket "2 surrounding an opening in the wall of a tank 3 within which the level of the liquid is to be controlled. The front wall of the plug I is provided with an opening 4 in which is threaded a second and smaller plug 5 having a circular flange 6 against which a switch supporting bracket 1 is clamped by means of a nut I. The plug 5 carries a tube 9 through which extends an operating shaft ll having a portion l2 bent at The interior end of the tube 9 is closed by a short bearing tube l4 and an end collar l5 and at its other end by a cylindrical nut I6 threaded into the tube 9. To seal the tube packing material ll is placed therein around the shaft H and is maintained and compremed in position by a spring 18. Upon the outer end of the shaft H outer insulating casing 26 directly secured to the bracket 1 which serves as the sole support for the switch. At one side of the casing 26 is mounted an attachment 21 into which conduit 28 for the reception of circuit wires may be threaded. Within the casing 26 is mounted a permanent magnet 26 supported on a current carrying plate 3| which is clamped thereagainst by means of a stud 32 (Figure 6), the magnet being insulated from the plate 3| by means of insulating sheets 33. The plate 3| is provided with a pair of upstanding ears, one of which at 34 serves as a terminal connection, the second at 35 being connected to a resilient arm 36 upon which is supported a stationary contact 31. A rotary insulating member 38 has a cam surface engaging the back of the resilient arm 36 and providing for adjustment thereof relative to the magnet 29. Upon the bottom wall of the casing 26 is mounted a metallic bracket 39 having a second terminal connector 4| thereon and pivotally mounting a magnetic arm 42 as by means of a shaft 43. Upon the arm 42 is rigidly mounted one end of a leaf spring 44 which carries at its upper end the movable contact 45 provided, as shown, with a reduced portion extending through the arm 42 so as to provide for relative motion between the contact 45 and spring 44 on the one hand and the magnetic arm 42 on the other. To the arm 42 is rigidly connected an actuating pin 46 and upon the bottom wall of the enclosure is mounted a resilient member 43 serving as a friction latch cooperating with the pin 46 to hold the arm 42 in the contacts disengaged position. At the lower right hand corner of the enclosure an insulating member 49 is pivotally mounted on a shaft 5|. Mounted upon the insulating member 49 are a pair of resilient arms 52 and 53 extending respectively above and below the pin 46. An inverted L-shaped bracket 54 is rigidly secured to the insulating member 49 and has its depending portion disposed between the abutment screws 24 and 25.

The operation of the switch will now be described. The cam member 38 is adapted to adjust the position oi the stationary contact so as to secure the desired gap between the magnetic arm 42 and pennanent magnet 29, With this adjustment once selected the o e" T at the top of the enclosure through which the cam is acoessible maybe sealed ofi to prevent accidental change in its adjustment. The parts as shown in the drawings are in the contacts disengaged position and the float i3 is in its lowermost post tion where it has moved bracket as counteicloclzn wise to force the finger 52 against the pin 8% and move the arm d2 against the attraction of the magnetfi to the disengaged position shown. The arm 32 is maintained in this position. by the friction latch (ill. its the float i3 is moved tip= weirdly by an increase in water level to the nos tion shown in clotted lines in Flguie the screw will engage the bracket E3 4 and move it in clocswise ection whereupon the "linger en gages and moves the contacts enga ed In operating to [1.5.13 force will be built up force overcomes the a magnet whereupon movable contact will be quickly snapped to i the attraction of the magnet rapidly decica with the air the resiliency oi the finger E32 and the natural buoyancy oi the float 58 will both operate efiect this uick opening move ment. As the arm 52 anoroaches the contacts engaged position the attraction of the 29 becomes rapidly greater until finally it the contacts into engaged position, Hence the unit provides for ouich maize ecod areal: opera tion of the switch. As so far described the finger sec might be a rigid element but it is desired that this also exert a resilient force to provide for over travel in the upward movement oi? float and also to provide to}: opening of the switch by other agencies against the force e2- erted by this finger. The difference in level oi the liquid in the tank to effect the operation of the switch may be adjusted between certain limits by adjusting the position oi the abutment screws Eli and 25 and ii it is desired to so be yond the range thus provided the length of the angle portion it of the pivot it may be increased.

While certain preiesred embodiments oi the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily ap= parent to those skilled in the art and the invention is to be given its broadest possible in terpretaticn within the terms of the following claims. 4

What is claimed is:

l. in an electric switch, a stationary contact; a movable contact arm supporting a movable contact to be engaged and disengaged with said stationary contact in response to movement of said arm, a permanent magnet adapted to attract said arm toward the engaged position of the contacts, latching means for maintaining said am in contacts disengaged position, re-

silient fingers disposed. at opposite sides of a part rigid with said arm, and means for chesting movement of said fingers to move said arm to its opposite extreme positions.

2. In an electric switch, a stationary contact, a movable contact arm supporting a movable contact to be engaged and disengaged with said stationary contact in response to movement of said arm, a permanent magnet adapted to attract said. am toward the engaged position of the contacts, latching means comprising a pin and spring means frlctionally acting thereupon tor maintaining said arm in contacts disengaged position, a pivoted member having a part rigid therewith extending to the exterior oi the switch, a pair 01 resilient fingers mounted on said memher and disposed at opposite sides of a part rigid with said arm whereby movement of said first mentioned part will apply a resilient force to said arm to effect its movement.

3. in a float operated electric switch unit, a plug adapted for insertion directly into the wall of the tent: or other receptacle, a second plug mounted in said first mentioned plug, a bearing tube mounted in said last mentioned plug and having a rotatable operating shaft extending therethrough, a float mounted on one end of said shaft to effect rotation thereof in response to changes in. the level of the liquid within the her mounted on the opposite end ovlo d s spaced adjustc s sooth us h...- v 6 l plug adapted insertio direct-l of the other: receptacle, seco mounted in, first ned plug ing tube mounted in and having opera through, a float mounted on one end oi shaft, a member mounted on the opposite of said shaft and provided with spaced abut ments, a flange on said last mentioned plug, a bracket having an opening receiving said plug, a nut threaded on said plug and clamping said bracket against said flange, and an. electric switch concerted on said bracket and having an operating member disposed between said abutments.

5. In an electric switch, a stationary contact, a movable contact arm supporting a movable contact to be engaged and disengaged with said stationary contact in response to movement of said arm, a permanent magnet adapted to attract said arm toward the engaged position of the contacts, latching means for maintaining said arm in contacts disengaged position, a pivot/memher having a part rigid therewith extending to the exterior of the switch and carrying a pair of resilient fingers disposed on. opposite sides of a part rigid with said contact arm, a rotatable member having opposite abutments thereon engageable with said first mentioned part to effect movement thereof in opposite directions to move said contact arm to its contacts engagecl and disengaged positions, and a float operatively connected to said rotatable member to efiect switch operating rotation thereof in response to the movement of the float.

6. in an electric switch, a stationary contact, a movable contact arm supporting a movable contact to be engaged and disengaged with said stationary contact in response to movement of said arm, a. permanent magnet adapted to attract said arm. toward the engaged position 01' the contacts, latching means engageable with a part connected to said arm when said arm is in its contacts disengaged position to maintain such position of the arm, a pivoted member havin a part rigid therewith extending to the exterior of the switch, a pair of resilient fingers mounted on said member and disposed at opposite sides of the part rigid with said arm, one of said fingers supplying the operating connection to move said arm to contacts disengaged position against the attraction of said magnet, the other finger supplying the operating connection to move said arm to contacts engaged position against the maintaining force of said latching means.

7. In an electric switch, a stationary contact, a movable contact arm supporting a movablecontact to be engaged and disengaged with said stationary contact in response to movement of said arm, a permanent magnet adapted to attract said arm toward the engaged position of the contacts, a spring element having a, surface frictionally engaging a part rigid with said arm when in its contacts disengaged position to hold the arm. in such position, a pivoted member having a part rigid therewith extending to the exterior of the switch, and a pair of resilient fingers mounted on said member and disposed at opposite sides of said part rigid with said arm and alternately engageable with said part in the opposite directions of rotation of said member to effect switching movement of the arm to contacts engaged and disengaged positions.

8. In an electric switch, a stationary contact, a movable contact arm supporting a movable contact to be engaged and disengaged with said stationary contact in response to movement of said arm, a permanent magnet adapted to attract said arm toward the engaged position of the contacts, a transverse pin rigidly connected to said arm, a spring member frictionally engaging said pin in the contacts disengaged position of said arm to maintain the arm in contacts disengaged position against accidental displacement, a switch operating member, and a pair of resilient fingers mounted to be moved with said operating memher, said fingers being disposed at opposite sides of said pin and being alternately engageable therewith in the opposite directions of movement of said switching member to chest movement of the arm into contacts engaged and disengaged positions.

9. In a float operated electric switch unit, an enclosure, separable contacts mounted within said enclosure and adapted to be operated to engaged and disengaged positions to effect the switching operation, means comprising a pin and resilient elements cooperating therewith for effooting operation of said contacts and further including a part extending through said enclosure, a rotatable shaft carrying a float at one end adapted to be disposed in a liquid in response to whose level the switch is operable, the opposite end of said shaft having an element rigidly mounted thereon for common movement therewith, said element carrying spaced abutments disposed at opposite sides of said part to effect movement thereof in opposite directions in response to rotation of the shaft as the float level rises and falls.

10. In a float operated electric switch unit, an enclosure, separable contacts mounted within said enclosure and adapted to be operated to engaged and disengaged positions to efiect the switching operation, means comprising a pin and resilient elements cooperatingtherewith for effecting operation of said contacts and further including a part extending through said enclosure, a rotatable shaft carrying a float at one end adapted to be disposed in a liquid in response to whose level the switch is operable, the opposite end of said shaft having an element rigidly mounted thereon for common movement therewith, said element carrying spaced abutments disposed at opposite sides of said part to effect movement thereof in opposite directions in response to rotation of the shaft as the float level rises and falls, said abutments being rigidly adjustable to vary the movement of the float necessary to sheet operation of the switch operating means.

11. In a float operated electric switch unit, a plug adapted for insertion directly into the wall of the tank or other receptacle, a second plug mounted in said first mentioned plug and having an operating shaft extending therethrough, a float mounted on one end of said shaft, a removable member mounted on the opposite end of said shaft for common movement therewith and being provided with spaced abutments, a bracket supported by said plug assembly, and an electric switch supported by said bracket and having an operating portion disposed between said abutments.

12. In a float tpei \ted electric switch unit, a plug adapted for insertion directly into the wall of the tank or other receptacle, 9. second plug mounted in said first mentioned plug, a bearing tube mounted in said last mentioned plug, and having a rotatable operating shaft extending therethrough, a float mounted on one end of said shaft to effect rotation thereof in response to changes in the level of the liquid within the tank, a removable member mounted on the opposite end of said shaft for common movement therewith and being provided with adjustable spaced abutments, a bracket supported by said second plug and an electric switch supported on said bracket and having an operating member disposed between said abutments.

JOSEPH J. ZELLER. 

